What Is Dimethicone?

The FDA over-the-counter skin protectant rule at 21 CFR 347.10 lists dimethicone, at 1 to 30 percent, among its skin protectant active ingredients, and federal rules define a skin protectant drug product as one that temporarily protects injured or exposed skin or mucous membrane surfaces from harmful or annoying stimuli and may help provide relief to those surfaces.

In a February 2022 report, the Cosmetic Ingredient Review Expert Panel concluded that dimethicone and related methicone ingredients are safe in cosmetics in the present practices of use and concentration when formulated to be non-irritating, with the exception that the available data are insufficient to make a determination of safety in products that may be incidentally inhaled when applied with airbrush devices.

Related cyclic siloxanes face more scrutiny. A 2024 European Commission regulation notes that since January 2018, EU law has restricted octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) in wash-off cosmetic products, and that in June 2018 the European Chemicals Agency identified D4, D5 and D6 as substances of very high concern with very persistent and very bioaccumulative properties, with D4 also identified as persistent, bioaccumulative and toxic. In September 2025, the EPA released a draft TSCA risk evaluation for D4 for public comment and independent peer review.